Assertion: Earthworm is brown- or clay-coloured.
Reason: Because of the presence of pigment porphyrin.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
C. If Assertion is true, but Reason is false.
D. If both Assertion and Reason are false.

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "Earthworm is brown- or clay-coloured." This is a factual statement about the coloration of earthworms.

2. **Analyzing the Reason**: The reason given is "Because of the presence of pigment porphyrin." This suggests that the brown or clay coloration of earthworms is due to a specific pigment.

3. **Verifying the Assertion**: Earthworms do indeed have a brown or clay color, particularly on their dorsal side. This is a characteristic feature of their appearance.

4. **Verifying the Reason**: The pigment porphyrin is known to be present in the body wall of earthworms. It is responsible for the brown coloration and serves a protective function against bright light.

5. **Establishing the Relationship**: Since the reason (presence of porphyrin) accurately explains why the earthworm has a brown or clay color, we can conclude that the reason is a correct explanation of the assertion.

6. **Final Conclusion**: Both the assertion and the reason are true, and the reason correctly explains the assertion.

**Final Answer**: Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

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